There's a point, during one of the lengthy black-and-white interview films that divide Boyzone's set into costume-changed chunks, when Shane Lynch says that getting back together as a band allows them to feel close to the deceased Stephen Gately.
From the screams of the crowd, they're not the only ones for whom the memory of their bandmate is very much alive - and it's perhaps why so much of what is actually their second tour since his 2009 death forms a eulogy.
Sat around a table at the front of the stage, the four surviving members of Boyzone crack open a bottle of wine, share some memories and toast their dead friend before breaking into "One More Song", their tribute from 2010's Brother. It follows "Gave It All Away" - the Mika-penned single that was the last to feature Gately's vocals, which were piped into The Hydro while the rest of the band sang live. This ran the risk of being a little too mawkish; but it's hard to be cynical when you're watching four grown men cry in front of you.
If it's hard to believe that Boyzone have been churning out pop hits for 20 years, the awkwardness of watching those old songs updated with X Factor style backing dancers tipped the hand a little.
"Picture of You" looked like something from Big Band Week, replete with dancing girls bearing red feather dusters; which were swapped for Mickey Mouse ears for "When The Going Gets Tough".
The band always seemed to cling to their innocence even as contemporaries adopted a raunchier style, so there was something uncomfortable about the backdrop of kaleidoscopic ladies' legs that accompanied the Mikey Graham-fronted "Ruby".